@astraluma kinda gradual--I spent about 10 years building 'em and fighting fires in prod, and another 7 testing them. Lotta papers throughout.
@astraluma I actually have a whole repo (distsys-class) for a crash course I teach on this stuff, and the outline is free for everyone. Lots of resources there.
(I've got a couple of distributed computing projects in mind, but there definitely feels like "you must be this trained" bar.)